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Pro-Ject Pre Box S2 digital DAC

Discussion in 'audio' started by miero, May 9, 2017.

  1. Stunsworth

    Stunsworth pfm Member

    So the DAC arrived this morning. First impressions...

    It’s tiny. I thought it would be small, but not as small as it is.

    The remote was built to a price. A very low price. I was hoping it would use the same control signals as my M-DAC, but no such luck. There is an optional metal remote available, but that costs around £60, so I’ll be sticking with cheap and nasty (more cheap than nasty).

    It look me ages to get it working. At first all I heard was a highly distorted signal. After much faffing about I tracked it down to the USB isolating transformer I use in cable between my Mac Mini and DAC, or rather ‘used’, once it was removed everything was hunky dory.

    The linear power supply works fine. The only issue was with its fan. When I saw the fan I thought it would be thermally triggered, but no, it was on all the time - and easily heard from my listening position. The seller recommends disconnecting the fan if it’s too loud, so off came the top of the box, and one snip later the fan was disconnected. After a few hours the power supply is barely warm, so there shouldn’t be any problems.

    I use Roon and HQPlayer for playback. I’m currently experimenting with playing everything as DSD - I do have a handful of DSD albums as well as PCM. I’ve found with my 2012 Mac Mini I can’t oversample PCM to anything higher than DSD 128, 256 and higher just gives a highly distorted sound, I guess the processor can’t cope.

    Finally, sound quality. Nothing to tell, I’ve got an ear infection which means my left ear is crap at the moment.
    sberry20118 and left channel like this.
  2. Itass

    Itass Member

    Thanks for sharing.
    Did you try to play Tidal-MQA?
    What linear power supply are you using?
    Enjoy the music and feel well!
  3. Stunsworth

    Stunsworth pfm Member

  4. left channel

    left channel Prominent Member

    This has caused quite a controversy. You're speaking of albums from the 2L label, yes? 2L delivered albums to Qobuz in "MQA CD" format, which they also call "MQA16 in WAV 16-44". Those albums play through the Qobuz app at 16/44.1 resolution. The Audirvana app also plays them at 16/44.1, not detecting and decoding them due to the way they are tagged in metadata. So, it was a surprise to Qobuz management and everyone else when, after Roon integration, Roon began detecting those as MQA albums and decoding them.

    Learning of this via user forums, the Qobuz folks investigated. After determining that 2L will not offer those albums in Redbook 16/44.1, they asked the label to more clearly tag each track as MQA. Also, there are no 24-bit Hi-Res tracks from 2L on Qobuz, but 2L management has stated that those will be available on Qobuz for download (not streaming, as I understand it) after a temporary third-party distribution business transition.

    And there you have it. I just saved you from having to wade through 13 pages of a thread on AudiophileStyle (formerly known as ComputerAudiophile), and several segues over to the Roon forums as well.
  5. Stunsworth

    Stunsworth pfm Member

    I streamed one of the 2L albums earlier this week in Roon/HQPlayer. It was identified as an MQA album by Roon and ‘unfolded’ accordingly.
    left channel likes this.
  6. sberry20118

    sberry20118 pfm Member

    Hi, nice to see another HQP user around here.

    I picked up this programmable remote on ebay, around $10. Much better to hold in the hand and big firm buttons. I picked up a couple, just to have one spare.

    Does a fine job for just changing inputs which is all I need. I leave the DAC volume at 0dB.

    Can't seem to upload pics here. Link here:

    Stunsworth likes this.
  7. Andrei

    Andrei Member

    Hey guys,
    I tried to look through the pages but there is just too much info to find what I want to know.
    So, basically, what I would like to know is this:
    1. If I dont plan to use it as preamp, is there any difference simply as a DAC between S2 and S2+?
    2. What about the sound? I would like a warmish, dark sound. Or at least totally neutral, I just dont want to hear any tint of brightness or glare. Can I find it with the Pro-Ject DAC?

    Many thanks!
  8. David W Brown

    David W Brown pfm Member

    Andrei likes this.
  9. jamesd

    jamesd pfm Member

    I'm listening to the headphone output right now and wouldn't characterize it as warmish/dark.
    Andrei likes this.
  10. left channel

    left channel Prominent Member

    The "S2+" is actually a minus. The S2D has dual DAC chips, the S2+ has one. The S2D has a detailed information display, the S2+ has very basic LED indicators. The S2D can handle DSD512, the S2+ only DSD256. The S2D can decode MQA over USB, the S2+ cannot.

    Most important, the S2D has received several firmware updates to fix problems you'll find discussed on this forum, while the S2+ has most of the same original bugs but has received no firmware update since release.Those bugs include very annoying popping sounds when switching sample rates.

    The S2 line targets a neutral, crisp, resolving sound. Everyone has different ears/brains, but I find it too bright, and regardless nobody would say it delivers your prefered warmish dark sound. This can be mitigated by a warm amp and warm headphones or speakers, but no matter what I try it's still too much the ESS sound signature for me. I've found I prefer DACs designed around AKM chips instead, for a smoother, forgiving, warmer sound.

    You may want to look at the new DS2 line from Pro-Ject. The DAC Box DS2 Ultra was designed around the AKM 4490 by a different team and probably sounds warmer. I saw it at AXPONA last year, but the environment was too loud for critical listening, so all I could note is that it in general matches the features of the S2+, not the S2D, and was around twice the size and price of the S2D.

    My preferred DACs are all AKM-based: the Schiit Modi 2U, Schiit Modi 3, and NuPrime DAC-9, plus the Fiio X5 3rd Gen DAC/DAP.
    sberry20118 and Andrei like this.
  11. atomic garden

    atomic garden Member

    I'm sharing all my findings regarding power supply and softwares that I use with the S2D. Long post :)

    Power supply. I've tested: Included switching power supply, 5v powerbank, USB port from computer (additional port, not the USB data cable), iFi iPower 5v, grounded iFi iPower 5v, Chinese Linear Power Supply.

    Based on my listening, the best ones are (in the following order): 1- grounded iFi 5v; 2- chinese LPSU; 3- ungrounded iFi 5v.

    I already had an iFi iPower for the S2D and was happy with that (significantly better than the included PS or 5v powerbank). But I finally found a Chinese LPS that has a 5v USB output + 12v output and also a 115v/230v switch. I have a 12v mini PC that I will use as an audio endpoint for Roon/HQPlayer. So a single linear power supply with 12v + 5v is what I wanted. This is the one I found: https://www.aliexpress.com/item/DAC...-linear-thermal-power-supply/32923450663.html

    I ordered one, and while it was on the way, I decided to try the JSGT (John Swenson's Ground Technique) on my iFi iPower. Bottomline is: all switching power supplies suffers from leakage current. Linear power supply blocks most of leakage current. iPower has a ultra low noise output across the audio bandwidth. But iPower is still a switching power supply and suffers from leakage current.

    The technique is basically connect the negative pole of the power supply to the ground pin of the same power outlet (or power strip) where the power supply is connected.
    More details here: https://audiophilestyle.com/forums/topic/37034-smps-and-grounding/

    I made my mod a little different (aesthetically better) than the original idea of using additional female connector + male connector. Mind that these 2 socket male plugs must be connected to the same power outlet (or power strip).

    This grounding made a great improvement. The Chinese LPS arrived later and it sounds good, it's sturdy and well-built. However the grounded iPower still sounds better.

    Software and configuration. I find DSD128 better than DSD256 or DSD512 on the S2D. I thought it strange and looked for explanations. I found out this: https://positive-feedback.com/audio-discourse/raising-the-sample-rate-of-dsd-is-there-a-sweet-spot/

    It's an article from an engineer involved in the creation of SACD at Sony. The article is from 2015 and now we have DSD256 or DSD512 capable hardware, like our Pro-Ject S2D. But capable doesn't mean optimized. Rough analogy: it's like a video-game capable of running a 4K game, but at 15 fps. I think DSD256 (at least on the S2D) still introduces some kind of distortion or artifact, because it doesn't sound as natural as DSD128. But again, this is all based on my listening impressions. One fact is that DSD128 already solves the problem of audio bandwidth noise that DSD64 presents.

    Source material: I mainly use Qobuz and Tidal, both on Roon. HiRes from Qobuz is great! MQA from Tidal is nice, as long as we decode only the 1st stage on Roon and then upsample on Roon or HQPlayer. Then I upsample to DSD128 on HQPlayer, using poly-sinc-short filter and DSD5v2 modulator. The filter is a matter of choice, but it seems that DSDv2 is the "correct" modulator for this DAC. I came to this conclusion only after having such a clean power supply. Roon upsampling instead of HQPlayer does a good job. HQPlayer upsamples better, but Roon using DSD128 "Precise, Linear Phase" filter and "5TH order (CLANS)" modulator comes close. I also use parametric EQ on Roon, and it squeezes the best out of my Shure SE846 IEMs.

    And the final piece after upsampling is JPlay Classic (only the driver, not JPLAY femto). I use Ultrastream engine, 500 Hz DAC Link and Kernel Streaming. 1000Hz DAC Link sounds even better, but it needs a dedicated audio computer so it doesn't have dropouts, but currently I'm using my work PC to everything. I also use Fidelizer software. I bought Audiophile Optimizer but still haven't tested because it also needs a dedicated audio computer. Using my mini PC for that is the next step.

    And finally on the Pro-Ject Control Panel, the lowest available ASIO Buffer Size, and Safe Mode unchecked.
  12. Andrei

    Andrei Member

    @left channel, thank you, this is what I was trying to find out.
  13. Pavan

    Pavan New Member


    New to the forum here. Just got my my S2D and powered it up with an IFI Ipower which I had.

    Great sound quality compared to the other similar priced DACs that I own.

    Have a issue with the filters. Playing off a Sonos Connect via coaxial and an Apple TV via optical. When I do toggle through the filters it just doesn’t make a difference in sound quality. Running the latest firmware SW version : 2.12. The package did come with a CD. But didn’t bother with it as it already was showing the latest firmware on the display.

    Everything else works like when I set it to Best it flips to Optimal Transient and when I switch to Test it flips to Brickwall. But no difference whatsoever.
    Toggle through the filters no difference again.

    Thought it was me who couldn’t make out the difference but also had some friends over to tell me if I was missing something or it was only my ears. But nor could they hear any difference.

    Am I missing something.

    Thanks in advance.
  14. left channel

    left channel Prominent Member

    Interesting question, @Pavan. Perhaps the filters only work with USB input. Anyone want to test this? We know MQA only works via USB. I've only used the coax and optical inputs a couple times, and would have to move some equipment around to test this now.
    Pavan likes this.
  15. Jose V.

    Jose V. Member

    I found out where this noise came from, and I want to share just in case somebody would face the same problem: when paying DSD direct, dac volume must be set to 0 db. That´s it. Problem solved.
    I have to say that I am very happy with the sound of this DAC, specially since I updated the USB cable to a quality short one. Sound is perfect now both optical and usb!
    left channel likes this.
  16. Bernd/K

    Bernd/K New Member

    Hi there
    Got the Pre Box S2 Digital and added the Stream Box S2 Ultra recently. Well the Accu Box S2 is around as well. Read another post by John Westlake (do not remember where - sry) that the USB power to DAC in the Streamer could be switched by software (other than Stack where this seems to be a real switch). Cannot find this option. If someone knows - would be glad to hear.

    Further I would be very interested to get further FW updates from John. Happy to pay for service. Feels not so great to read about his relation with Pro-Ject. To be frank my experience w/ their support does not make me sleep lightly ...

    Best regards
  17. skanderborg

    skanderborg Member

    To illustrate this firmware bug, I attach some photos from my oscilloscope.

  18. skanderborg

    skanderborg Member

    Sorry, I don't know how to properly insert images. Could you give me an advice please?
    How to insert a picture from onedrive?
  19. left channel

    left channel Prominent Member

    I don't use OneDrive and that is an example of why. A few years ago they made it impossible to share an image with a direct url, and I don't know if they ever fixed it. I think you can do it from Google Drive. Or use photo-sharing sites like imgur, or place them in a personal website directory. You can also post them to another forum that hosts images, then link to the urls of the images there. On pinkfishmedia the image hosting feature is turned off, but other forums that use the same XenForo platform have enabled it.
  20. skanderborg

    skanderborg Member

    Thank you, I try to insert pictures again from Google Drive.


    It seems, direct links OK, but direct picture insert does not work.

    left channel likes this.

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